Depression is one of the most common mental disorders among children and adolescents, affecting as many as 25% of adolescents by age 18. Despite the substantial body of research on the epidemiology and treatment of youth depression, very little information exists regarding the services for youth depression in typical health care settings, particularly managed-care. This application addresses this dearth of information with a study employing quasi-experimental methods to examine the naturalistic study of antidepressant treatment in a general adolescent population (ages 12 to 18) in a large HMO. While the majority of the evaluation plan is exploratory and hypothesis-generating (consistent with the developmental nature of the R21 mechanism), this application is specifically powered to test one primary hypothesis: whether outcomes are better for depressed children receiving "adequate" SSRI pharmacotherapy versus inadequate treatment, over a 6-month observation window (N=332). We will also conduct exploratory analyses of factors that may affect adequacy of pharmacotherapy (including provider characteristics, side effects, and other treatment barriers), and conduct a descriptive analysis of actual treatment patterns. Although primarily focused on pharmacotherapy, we will report on the broader array of treatment services received by these youth. Information will be collected through electronic medical records (EMR) and supplemental interviews of the youth and parents. The proposed study is an important step (along with additional efficacy studies) in deciding how to best proceed with the promotion and dissemination of pharmacotherapy standards and algorithms. This study will illuminate whether outcomes associated with naturalistic but adequate SSRI pharmacotherapy differ from outcomes achieved with "idealized" pharmacotherapy provided in randomized clinical trials (RCTs). If so, subsequent analyses will generate hypotheses about factors that may be related to the attenuation of these outcomes relative to outcomes achieved in RCTs. This will in turn help future studies to identify and overcome barriers to improving pharmacotherapy for depressed youth in practice settings. Consistent with the purpose of the developmental grant (R21) program (PA-00-073) this project will allow us to test quasi-experimental procedures that can be used in future studies to examine the effectiveness of usual care practices for depressed youth more broadly. We believe the most significant aspect of this research is how the results will inform the promotion of appropriate pharmacologic treatment of depression in practice settings. This research will help to refine an important procedure for obtaining timely, clinically useful data where the results from RCTs have been out-paced by the widespread increase in SSRI use in practice settings.